Human skin is composed of three primary layers of tissue: the epidermis, the dermis, and the hypodermis. The epidermis is divided into several sublayers, including stratum corneum, stratum granulosum, stratum spinosum, and stratum basale (from outer most to inner most). Stratum corneum, the outermost layer of the epidermis, functions to form a primary barrier to protect the skin from external physical and chemical stimuli, microbial infection, etc. and to control water evaporation from body fluids for the maintenance of skin homeostasis (Lee, Seung-Heon; Chung, Jun; Ahn, Sung-Gu; Kang, Jin-Soo; Kwon, Oh-Gyu;/Korean Dermatological Association, v. 32(4), pp. 599-603, 1994). The substances that keep the skin soft and tight are mostly dependent upon the water present in the stratum corneum. The water content of the stratum corneum highly depends on the amount of sebum in the epidermis and the aqueous component of the stratum corneum, so-called natural moisturizing factor (NMF) (Spencer T S: “Water and the horny layer”, J. Soc. Cosmet. Chem. 27: pp. 63-72, 1976). The sebum covers the skin surface to prevent transepidermal water loss. In contrast, the NMF readily absorbs water and lowers the surface tension of the skin to prevent the repellence of water from the keratinocytes, further making a direct effect on the skin moisturization (Pyo, Kyung-Chan; Kim, Hong-Jik; Kim, Young-Geun;/Korean Dermatological Association, v. 26, pp. 10-15, 1988).
The stratum corneum, once considered to merely have a buildup of dead cells and bodily waste, have various components and functions of its own, which protect the body against external physical and chemical stress, microorganisms, etc. and properly control the water evaporation from body fluids to maintain skin homeostasis. The substances that function to keep the skin soft and tight are mostly dependent upon the water content of the stratum corneum (Choi, Eun-Young;/Korean Dermatological Association, v. 4, No. 2, pp. 2).
The conventional moisturizer most popular as a solution to this problem is polyhydric alcohol, such as glycerin, propylene, sorbitol, etc. Microbe-derived sodium hyaluronate is also in use as a moisturizer. As people today use a lot of chemical artificial ingredients, their skin is susceptible to dehydration, irritations, allergies, etc.
Further, a succession of recent detections of toxic substances from the disinfectants for humidifiers results in a phobia about chemical products.
Korean Patent Publication No. 10-2004-0021695 discloses “a moisturizer and a cosmetic material and a topical formulation including the same”, which patent provides a moisturizer having excellent moisture retention characteristic and high stability at high temperatures of 40° C. or above, and a cosmetic material and a topical formulation including the moisturizer. For this purpose, the cited patent describes a moisturizer and a cosmetic material and a topical formulation including the same, which moisturizer comprises: (a) an ester compound composed of at least one of glycerin and its condensate, a linear-chain saturated fatty acid having 16 to 28 carbon atoms and a saturated aliphatic dibasic acid having 16 to 28 carbon atoms, where the ester compound has hydroxyl groups half as many as the total number of the hydroxyl groups in the at least one of the glycerin and its condensate; (b) an aqueous dihydric alcohol; and (c) an aqueous, at least trihydric alcohol.
Korean Patent Publication No. 10-2013-0134803 discloses “a moisturizing cosmetic composition comprising a propolis-containing nanovesicle”, where the moisturizing cosmetic composition includes a defined amount of the propolis-containing nanovesicle.
Korean Patent Publication No. 10-2014-0117862 is directed to “an oil-in-water type silicone-emulsified moisturizing cosmetic composition having a transparent property, a preparation method for the same, and a moisturizing cosmetic containing the same”. The cited patent describes an oil-in-water type silicone-emulsified moisturizing cosmetic composition that contains a polyol-based moisturizing component and an aqueous moisturizing component at high concentration to maximize the skin moisturization and promotes the compatibility between silicone and the aqueous phase including the polyol-based moisturizing component and the aqueous moisturizing component both contained at high concentration not only to improve the finishing tough overcoming sticky sensation and poor softness caused by the presence of the high-concentration polyol-based moisturizing component but also to attain a transparent property.
Korean Registered Patent Publication No. 10-1152315 (published on Jun. 11, 2012) discloses “a method for preparing a fat composition for chocolate and confectionary using enzymatic trans-esterification”.
Accordingly, there is an urgent demand for developing a plant fat composition for cosmetic preparation that is available for the consumers with a safe conscience and enables the preparation of cosmetic materials using eco-friendly, nature-originated ingredients to cope with the environmental factors such as fine dust and particularly having excellent moisturizing, antioxidative and/or antimicrobial effects.